Hybrid fiber coaxial (HFC) networks are rapidly evolving to support a variety of telecommunications services in addition to traditional broadcast-type video services. In particular, HFC networks are being utilized to provide data services, including high speed Internet access. Cable network operators are expected to be providing medium to high penetration rate telephony services in the near future.
Telecommunications services, such as plain old telephone service (POTS), can be provided through the use of a unit located on the side of a home, or in a centralized location in the residence (or business). This unit, which forms the interface between the HFC network and the telephone-based customer premise equipment (CPE) can be referred to as a “communications gateway”, or CG. The CG contains various line cards that provide an interface between the HFC network and traditional telephones, for example, using a “POTS card” located in the CG. The CG transmits and receives data over the HFC network using a particular protocol, which in a preferred embodiment is the Data Over Cable Service Interface Specification (DOCSIS), using the Media Gateway Control Protocol (MGCP) as the signaling protocol for telephony applications.
With a POTS card in place, an interface to a twisted-wire pair is provided and telephones in the residence can be used in a conventional manner, with all of the phones connected to a single twisted-wire pair connected in a bus configuration to the phone outlets throughout the building. Alternatively, “home run” wiring may be utilized, with point-to-point connections being established between a centralized location and a particular telephone outlet or set of outlets. The advantage of home run wiring is that several phone lines can easily be supported in the home, and phones in one area can be assigned one telephone number, distinct from other numbers used for phones in other areas. Multiple POTS cards are typically used to support multiple telephone lines.
At the present time, however, most homes and small businesses do not have a “home run” wiring installation, but instead use the simple bus structure that connects to the telephone network at a defined demarcation point. In some instances, a customer may desire to have a low cost basic telephone line from the local telephone company, but will also want to have additional lines supplied by an HFC network operator. In some homes, additional twisted-wire pairs will not be available. These limitations necessitate other means of interconnecting telephones or other data/telecommunications devices with the CG. In other circumstances, a twisted wire pair may be available, but the services to be provided may go beyond a single POTS line.
Since the in-home wiring may not be optimal in terms of architecture, and may also be carrying a POTS signal supplied by a telephone company, it is necessary for the HFC network operator to consider the use of alternative types of in-home communications. These types of communications can include in-home wiring networks, the provision of data over the existing telephone line (above the POTS spectrum), or using the in-home electrical power network.
FIG. 1 is a diagram of an exemplary conventional network architecture utilizing a communications gateway (CG) between an HFC network and a residence. As shown, CG 10 is in communication with a Cable Modem Termination System (CMTS) 12 over an HFC network 14. CMTS 12 is in further communication with a call management system (CMS) 16 that communicates with both a public switched telephone network (PSTN) 18 and an IP network 20. As illustrated in FIG. 1, CG 10 communicates on the residence side with a plurality of devices 22 via an in-home network 24. Use of in-home networking protocols will allow for new services to be supported from CG 10, and will allow for the use of existing CPE (e.g., standard telephones) to be used in implementing at least some of these new services. However, since the HFC network uses a specific protocol, it is likely to be distinct from and incompatible with in-home networking protocols, making difficult any communication between the HFC network and the home.